Azo dye.



UNTTED STATES Patented May 12, 1903.

PATE T O ICE.

MYRTlL KAHN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OF ELBERFELD (30., OF NElV YORK, N. Y., A CORPORATION OF NEW YORK.

AZO DYE.

@PJQCIFICATION forming part of Letters Patent No. 727,962, dated May 12, 1903.

Application filed February 16, 1903- Serial No. 143,629. (No specimens.)

To all whom it may concern:

Be it known that I, MYRTIL KAHN, doctor of philosophy, chemist, residing at Elberfeld, Germany, (assignor to the FARBENFABRIKEN or ELBERFELD 00., of New York,) have invented a new and useful Improvement in Azo Dyes; and I do hereby declare the following to be an exact and clear description of my invention.

My invention relates to the production of new and valuable azo dyestuffs by combining with 2 :6-dioxynaphthalene the diazo com-- pounds of ortho-amidophenol sulfonic acids having the general formula: 1

one, 1 2 06H? so a (X meaning a hydrogen atom, which can be replaced by halogens NO SO H, or OH such as ortho-amidophenol sulfonic acids, ortho-amidocresol sulfonio acids, ortho-amid0- phenolnitro-sulfonic acids, ortho-amidophenol-chloro-sulfonic acids, ortho-amidophenol disulfonic acids, or the like. v

The new azo dyestuffs thus obtained are brownish-black powders soluble in water with from a reddish-violet to bluish-violet color, turning blue on adding a solution of sodium carbonate and dyeing wool from acid-bath from bluish-red to blue shades, turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents. The black shades thus obtained possess a great fastness to the potting process, which is a finishing process for woolen piece goods. In this process the goods are entered into boiling water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and, according to the effect desired, the potting may be repeated several times.

In carrying out my process practically I can proceed as follows, the parts being by weight: Nineteen parts of ortho-amidophenol-para-sulfonic acid having the formula:

so n

are diazotized in the usual manner, and the resulting diazo compound is stirred into a mixture of sixteen parts of 2:6-dioxynaphthalene with ice-water. Caustic-soda lye is added until the mixture is alkaline. The dioxynaphthalene enters into solution andthe formation of the dyestuff begins. After being stirred for some time the excess of canstic-soda lye is neutralized by means of hy: drochloric acid, and the new dyestuff is precipitated by the addition of common salt, filtered ofi,'and dried.

Thenew coloring-matter thus obtained is in the shape of the sodium salt, when dry and pulverized, a brownish-black powder soluble in water and in alcohol to a violet so: lution and soluble in concentrated sulfuric acid of 66 Baum with a bluish-red color, which is changed to violet on adding a small quantity of ice, a brownish-black precipitate being obtained by the addition of a larger quantity of ice. It dyes wool from acid-bath bluish-red shades. By subsequently treating the dyed fiber with chromium compounds reacting as oxidizing agentssuch as chr0- mates, bichromates, or the like-the shades are changed to black, distinguished for great fastness to the potting process. They also resist milling and Washing and possess a good fastness against the action of light.

Having now described my invention, what I claim is- 1. The herein-described new azo dyestuffs derived from ortho-amidophenol derivatives having the above-given formula and 2:6-dioxynaphthalene, which, when in a dry state, are brownish-black powders soluble in water with from a reddish-violet to bluish-violet color turning blue on adding a solution of so of a small quantity of ice, a brownish-black precipitate being obtained by addition of a larger quantity of ice; dyeing Wool from acidbath bluish-red shades which are changed to black by a subsequent treatment with chromium com pounds reacting as oxidizing agents, substantially as described.

In testimony whereof I have signed my name in the presence of two subscribing Witnesses.

MYRTIL KAI-IN. WVitnesses:

OTTO Home, J. A. RITTERSHAUS. 

